Composite structures and methods of forming composite structures

ABSTRACT

Composite structures and methods of forming composite structures are provided. The composite structures can include one or more composite structure components. Each composite structure component is formed from a composite panel that includes one or more sheets of material. The sheets of material include a thermoplastic material and a plurality of reinforcing fibers. A composite panel can be formed in three dimensions to form a composite structure component. Multiple composite structure components can be fused to one another to form a composite structure. In addition, each composite structure component and the composite structure formed therefrom can include an aperture. An interior volume can be formed between adjacent composite structure components. Methods for forming a composite structure can include a step of simultaneously molding and fusing composite structure components.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/472,397, filed Mar. 16, 2017, the entiredisclosure of which is hereby incorporated herein by reference.

FIELD

The present disclosure provides composite structures and methods offorming composite structures. More particularly, embodiments of thepresent disclosure utilize a material having reinforcing fibers embeddedin a thermoplastic material that is molded into a desired configurationto create composite structures.

BACKGROUND

Composite materials have a variety of advantages as compared toalternate materials, such as steel, aluminum, or wood. For example,composite materials can be used to form structures having intricateshapes, allowing strength and aesthetics to be optimized. In addition,the potential strength to weight ratio of structures formed using carbonfiber composites is very high. Products formed from carbon fibercomposites, commonly referred to as simply “carbon fiber”, are alsopopular with consumers.

Widespread adoption of composite materials has been limited by therelatively high cost of forming composite or carbon fiber structures.These costs are a result of various factors, such as the cost of thematerials themselves, and the labor-intensive processes used to formsuch structures. For example, composite structures are typically formedby laying multiple sheets of composite material in a mold. Each sheetincludes fibers that are oriented along one or several directions orplies, and that generally extend from one edge of the sheet to another.More particularly, different layers of material, having the associatedply or plies oriented in a specific direction, are placed in a mold andset into a final form using a two-part epoxy. In addition to beingtime-consuming and labor-intensive, such techniques are prone to defectswhen used to form complex, hollow structures time efficiently. Suchmethods are also unable to take full advantage of the strength to weightratio of the material. For example, conventional composite structuresthat are otherwise capable of withstanding designed loads requireadditional reinforcement in order to provide consumer friendly endproducts that are resistant to impacts and that have acceptable productlifetimes. In addition, composite structures have typically usedthermoset materials that are relatively brittle and difficult torecycle.

As an alternative to composite structures that are formed by layeringmultiple sheets of material in a mold, structures can be formedrelatively quickly and cheaply using injection molding. However, thestructures formed using such processes are typically quite weak. Inaddition, it is impossible to form certain three-dimensional shapesusing injection molding.

SUMMARY

Embodiments of the present disclosure provide composite structures andmethods of forming composite structures. The composite structurescomprise composite panels that include one or more sheets ofthermoplastic fiber reinforced material. The composite panels cancomprise slits or apertures formed therein. In accordance with furtherembodiments of the present disclosure, multiple composite panels can bejoined to one another to form composite structures. The compositestructures can include at least portions that are hollow. Each compositepanel in a composite structure can be joined to at least one othercomposite panel by a welding process.

In accordance with embodiments of the present disclosure, each compositepanel comprises one or more composite sheets of material that include aplurality of fibers embedded in a thermoplastic material. In accordancewith at least some embodiments of the present invention, at least one ofthe sheets of material in a composite panel includes fibers that arerandomly oriented. Moreover, the randomly oriented fibers may berelatively short, such that most of the fibers do not extend from oneedge of the sheet to another. Alternatively or in addition, at least oneof the sheets of material in a composite panel includes unidirectionalfibers, with at least most of the fibers extending between differentedges of the sheet of material. The composite panel can additionallyinclude one or layers of core or spacer material between otherwiseadjacent sheets of material. In accordance with at least someembodiments of the present invention, the composite panel includes atleast one slit or aperture that is within a perimeter of the compositepanel. In accordance with still further embodiments of the presentdisclosure, the slit or aperture extends through all of the sheetsmaking up the composite panel.

A composite structure as disclosed herein can incorporate multiplecomposite panels. In accordance with at least some embodiments of thepresent disclosure, a composite structure includes a three-dimensionalcomposite structure component that includes at least one composite panelthat is joined to a second composite structure component that includesat least one composite panel. The second composite structure componentcan also be formed in three dimensions. In addition, each of thecomposite structure components, and the resulting composite structure,can have an aperture formed within an outer perimeter thereof. Thecomposite structure can also feature at least one hollow section,between adjacent portions of the first and second composite structurecomponents. In accordance with further embodiments of the presentdisclosure, the first and second composite structure components can bejoined to one another by welding. Moreover, a welding strip in the formof the thermoplastic material of the panels, either alone or incombination with one or more plies of fibers, can extend across a jointor interface between the first and second composite structurecomponents.

Methods of forming composite panels can include layering multiplecomposite sheets of thermoplastic impregnated fiber materials, andfusing the multiple sheets using heat and pressure. The different sheetscan be selected to provide fibers of a desired tensile strength, length,and orientation or orientations relative to the perimeter of therespective sheet. In addition, the sheets can be oriented with respectto one another to provide strength in desired directions.

Methods of forming composite structures in accordance with embodimentsof the present disclosure include placing a composite panel in a femalemold and applying pressure to the composite panel with a male mold, toform a three-dimensional composite structure component. The compositepanel can have a slit or aperture formed therein prior to placing thepanel in the molds. A first three-dimensional composite structurecomponent can be joined to a second three-dimensional compositestructure component to form a completed composite structure. Inaccordance with further embodiments, the composite structure can includemore than two composite structure components. Moreover, at least some ofthe composite structure components can be flat, rather than formed inthree dimensions. The composite structure can include an aperture withinan outside perimeter of the structure that extends through multiplecomposite structure components. Alternatively or in addition, thecomposite structure can include one or more hollow portions formedbetween adjacent sections of composite structure components.

Methods of joining composite structure components include weldingadjacent components to one another. Welding adjacent components caninclude applying heat to the area of the joint, to raise the temperatureof the components to a point that is greater than the glass transitiontemperature and up to the melt temperature of the thermoplasticmaterial. In accordance with at least some embodiments of the presentdisclosure, a joint between adjacent composite structure components isformed by abutting edges of the adjacent components. In addition, awelding strip, which can be a strip of the same thermoplastic materialpresent in the composite structure components, with or without fibers,can be placed along the joint while heat is applied to the joint. Inaccordance with still further embodiments of the present disclosure, thewelding strip can be located within a hollow area of the compositestructure, and can be pressed against the composite structure componentsthat are being joined by an inflated bladder, a mandrel, or the like,while heat is being applied to form the joint.

Additional features and advantages of embodiments of the presentdisclosure will become more readily apparent from the followingdescription, particularly when considered together with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example composite structure in accordance withembodiments of the present disclosure;

FIG. 2 depicts an example composite structure in a cross-section takenalong line B-B′ of FIG. 1;

FIGS. 3A-B depict composite structure components in accordance withembodiments of the present disclosure;

FIG. 4 depicts a composite panel in accordance with embodiments of thepresent disclosure in a plan view;

FIG. 5 depicts a composite panel in accordance with embodiments of thepresent disclosure in a side elevation view;

FIG. 6 depicts a sheet of thermoplastic reinforced material inaccordance with an embodiment of the present disclosure;

FIG. 7 depicts a sheet of thermoplastic reinforced material inaccordance with another embodiment of the present disclosure;

FIG. 8 depicts a sheet of thermoplastic reinforced material inaccordance with another embodiment of the present disclosure;

FIG. 9 is a flowchart illustrating aspects of forming a compositestructure in accordance with embodiments of the present disclosure;

FIG. 10 depicts a preform step in accordance with embodiment of thepresent disclosure; and

FIG. 11 depicts a final shaping and forming step in accordance withembodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 depicts an example composite structure 104 in accordance withembodiments of the present disclosure, and FIG. 2 depicts the compositestructure 104 in a cross-section taken along line B-B′ in FIG. 1. Inthis example, the composite structure is a main portion of a bicycleframe. However, it should be appreciated that other products comprisingunitary or multipart structures can be formed using embodiments of thepresent disclosure. In particular, composite structures 104 as disclosedherein can be used to form all or portions of various products,including products having complex shapes, a high-strength to weightratio, and excellent impact resistance. Moreover, as described herein,composite structures 104 can be formed with reduced costs, includingreduced labor and production costs, and with reduced manufacturing time,as compared to conventional composite structures 104.

The example composite structure 104 is formed using multiple compositestructures or component parts 108 a and 108 b (see FIG. 2), and includesan aperture 112 (see FIG. 1) formed within an outside perimeter of thecomposite structure 104. The composite structure components 108 areformed in three dimensions, and when joined create a hollow space orinterior volume 120 between adjacent interior portions or surfaces 124 aand 124 b of the components 108. In addition, the composite structurecomponents 108 are joined to one another along corresponding inside edgeportions 128 a and 128 b and outside edge portions 132 a and 132 b. Inaccordance with at least some embodiments of the present disclosure, therespective inside edge portions 128 a and 128 b and outside edgeportions 132 a and 132 b are welded to one another, forming a weldedjoint 136. In accordance with at least some embodiments of the presentdisclosure, a welding strip 140 can be provided adjacent to some or allof the joints 136. Alternatively or in addition, a composite structurecomponent 108 can include a joggle that overlaps some or all of thejoints 136.

Each composite structure component 108 may, for example, comprise onehalf of the completed composite structure 104. In addition, the firstcomposite structure component 108 a and the second composite structurecomponent 108 b may mirror one another. However, such a configuration isnot a requirement. In addition, a composite structure 104 can includeany number of composite structure components 108. Moreover, a singlecomposite structure component 108 can be joined to multiple othercomposite structure components 108.

With reference now to FIGS. 3A-B, example composite structure components108 are shown in a plan view looking at the interior surfaces 124 a and124 b of the respective components 108 a and 108 b. More particularly,FIG. 3A illustrates the inside surface 124 a, the inside edge portions128 a, and the outside edge portions 132 a of the first compositestructure component 108 a, while FIG. 3B illustrates the inside surface124 b, the inside edge portions 128 b, and the outside edge portions 132b of the second composite structure component 108 b.

The inside edge portions 128 and/or the outside edge portions 132 can becontinuous, or can include discontinuities. Moreover, the inside edgeportions 128 and/or the outside edge portions 132, can be provided inmultiple sections. The example composite structure components 108depicted in FIGS. 3A and 3B include continuous inside edge portions 128.The example composite structure components 108 additionally featureoutside edge portions 132 that include discontinuities. In particular, afirst discontinuity is present in an area corresponding to a seat postaperture 304, and second and third discontinuities are present in areascorresponding to the top 308 and bottom 312 of a head tube portion ofthe composite structure 104. As a result of this configuration, theoutside edge portions 132 of the example composite structure components108 are provided in multiple sections: a first section 316 a and 316 bbetween the top 308 and bottom 312 of the head tube portion, a secondsection 320 a and 320 b between the bottom 312 of the head tube portionand the seat post aperture 304, and a third section 324 a and 324 bbetween the seat post aperture 304 and the top 308 of the head tubeportion.

In addition, one or more auxiliary apertures can be formed between theinside edge portion 128 and the outside edge portion 132 of one or bothof the composite structure components 108. For example, a firstauxiliary aperture 328 a may be formed in first composite structurecomponent 108 a and a corresponding first auxiliary aperture 328 b maybe formed in the second composite structure component 108 b toaccommodate a bottom bracket assembly. As another example, a secondauxiliary aperture 332 may be formed in the first composite structurecomponent 108 a only, to provide a mounting point for a component oraccessory.

In accordance with embodiments of the present disclosure, each compositestructure component 108 is formed from a composite panel 404. An examplecomposite panel 404, before the forming process has been performed, isdepicted in FIGS. 4 and 5. As shown, the composite panel 404 maycomprise a planar panel prior to molding to form a composite structurecomponent 108. The composite panel 404 generally includes a plurality ofcomposite sheets 504 that have been fused or welded to form thecomposite panel 404. Each composite sheet 504 includes a thermoplasticmaterial 508 and a plurality of fibers 512 embedded therein. Thecomposite sheets 504 are fused to one another through the application ofheat and pressure. FIG. 4 depicts a composite panel 404 after trimmingof the completed composite panel 404 or the individual sheets 504, todefine inside edges 516 and outside edges 520. The inside edges 516define an aperture 524 in the composite panel 404. Some or all of theinside edges 516 may be coincident with the inside edge or edges 128 ofthe formed composite structure component 108. In addition, some or allof the outside edges 520 may be coincident with the outside edge oredges 132 of the composite structure component 108. Alternatively, theedges 516 and 520 can approximate the respective edges 128 and 132 ofthe composite structure component 108. As discussed in greater detailelsewhere herein, the edges 128 and 132 of the composite structurecomponent 108 can be formed by trimming after the composite panel 404has been molded into the three-dimensional shape of the compositestructure component 108.

Different composite sheets 504 within a composite panel 404 can havedifferent fiber 512 orientations and configurations, as illustrated inFIGS. 5-8. For example, one or more composite sheets 504 within acomposite panel 404 can feature relatively long fibers 512 that canextend between adjacent edges of the sheet 504. Such a configuration isillustrated in FIGS. 6 and 7, with fibers 512 that extend betweendifferent outside edges 520, or between an outside edge 520 and aninside edge 516. The composite sheets 504 a and 504 b with relativelylong fibers 512 can have those fibers configured unidirectionally, suchthat the fibers 512 extend in the same general direction. In accordancewith further embodiments, the fibers 512 can be parallel orsubstantially parallel to one another. As used herein, fibers 512 aresubstantially parallel if they extend along a common direction +/−10°.Moreover, two or more sheets 504 having relatively long fibers 512 canbe aligned such that the fibers 512 of one composite sheet 504 are at anonzero angle with respect to the fibers 512 of another one of thecomposite sheets 504. Alternatively or in addition, one or more of thecomposite sheets 504 can have relatively short, randomly oriented fibers512. More particularly, the fibers 512 can be randomly oriented in atleast a plane encompassing the edges of the composite sheet 504 whenthat sheet 504 is in a flat configuration. FIG. 8 depicts a compositesheet 504 c having randomly oriented fibers 512 embedded within athermoplastic material 508. As shown, the fibers 512 in this example arerelatively short, and generally do not extend between opposite edges 516and 520 of the composite sheet 504. In accordance with still otherembodiments, the fibers 512 within a composite sheet 504 can be woven,with subsets of fibers and selected angles with respect to other subsetsof fibers within the composite sheet 504.

An example layout is illustrated in FIG. 5, with a first composite sheet504 a comprising a first layer that has relatively long fibers 512oriented in a first direction, a second composite sheet 504 b comprisinga second layer having relatively long fibers 512 oriented in a seconddirection, which in this example is orthogonal to the first direction,and a third composite sheet 504 c comprising a third layer havingrelatively short fibers 512 in random orientations within thethermoplastic material 508. In an exemplary embodiment, the firstcomposite sheet 504 a may form an inside surface 124 of a finishedcomposite structure component 108, while the third composite sheet 504 cmay form an exterior surface of the finished composite structurecomponent 108. In addition, embodiments of the present disclosure caninclude spacer or filler sheets or layers between sheets 504 containingthermoplastic material 508 and fibers 512. A spacer of filler layer afiller material, such as a glass or foam embedded in or impregnated witha thermoplastic material 508.

In accordance with at least some embodiments of the present disclosure,the composite panel 404 is formed as a planar or substantially planarpanel from textile like composite sheets 504. The individual sheets mayor may not be flexible at room temperature. Each of the composite sheets504 may be in the form of a substantially continuous sheet, for examplein the shape of a rectangle, that is trimmed to form edges 516 and 520,and one or more apertures 524, before they are initially stacked withone another to form the layup of the composite panel 404. Alternatively,some or all of the composite sheets 504 may be trimmed after being fusedto one or more other composite sheets 504. Whether formed in individualor sub-sets of composite sheets 504, or in a completed composite panel404, the edges 516 and 520 generally follow a pattern that approximatesthe shape of the composite structure component 108 that will be formedfrom the composite panel 404. In addition, all or portions of the edges516 and 520 can include fringes or slots, and one or more apertures 524can be formed within the outer perimeter of the composite panel 404, toassist in obtaining a desired three-dimensional composite structurecomponent 108 from the composite panel 404.

With reference now to FIG. 9, aspects of a process for producing acomposite structure 104 in accordance with embodiments of the presentdisclosure are depicted. Initially, at step 804, a single compositepanel 404 is formed. Forming the composite panel 404 can includeselecting or forming from a larger piece of material one or more sheets504 of appropriate size. In addition, forming the composite panel 404can include creating a layup or stack of composite sheets 504, withdifferent composite sheets 504 having a selected fiber 512 andorientation relative to the other sheets 504. The stack can include oneor more spacer layers containing a filler material, but not fibers, andthe same thermoplastic material as the thermoplastic material 508 of theother sheets 504. The composite sheets 504, and any spacer layers,within the stack are then fused using heat and pressure, to form thecomposite structure 404. More particularly, forming the composite panel404 can include heating the thermoplastic material 508 in the compositesheets 504 to greater than the above the melting point of thethermoplastic material in order to fuse the composite sheets 504 to oneanother. The pressure applied during the composite panel 404 formingprocess can be greater than 100 psi. In further embodiments, thepressure applied during the composite panel 404 forming process can begreater than 400 psi. In still other embodiments, the pressure appliedduring the composite panel 404 forming process can be greater than 1000psi. The composite panel 404 may have a generally flat or planarconfiguration, Alternatively, the panel 404 may be given a contour ormay be shaped in three-dimensions, for example to approximate a finalshape of the composite structure component 108 formed from the compositepanel 404, and/or the final mold. In accordance with at least someembodiments of the present disclosure, the individual composite sheets504 may be trimmed to form inside 516 and outside 520 edges prior tofusing. Alternatively, the composite sheets 504 may be provided in acommon shape, such as rectangles, and fused to form a composite panel404 that is then trimmed to form the edges 516 and 520.

The composite panel 404 is then disposed on or adjacent a preform mold1004 (see FIG. 10) (step 908). The composite panel 404 is made pliableby applying heat (step 912). For example, a heated fluid or a matchedmold 1008 can be applied to a side of the composite panel 404 oppositethe side adjacent the preform mold 1004, causing the composite panel 404to conform to or approximate the shape of the mold 1004. Alternativelyor in addition, the preform mold 1004 itself can be heated. In general,the heating of the composite panel 404 is controlled so as to maintainthe temperature of the thermoplastic material 508 within the fusedcomposite sheets 504 of the composite panel 404 to a temperature that isat or above the glass transition temperature and at or below the meltingtemperature of the thermoplastic material 508. The preform molding stepforms a preformed composite panel 1104. In accordance with at least someembodiments of the present disclosure, the step of preforming, to createa preformed composite panel need not be performed, and the compositepanel 504 can be placed in a final mold as a planar or substantiallyplanar element.

At step 916, the preformed composite panel 1104, or if no preforming isperformed, the composite panel 504, is placed in a final mold 1108 (seeFIG. 11). Moreover, as depicted in FIG. 11, a set of preformed compositepanels 1104 a and 1104 b or composite panels 404 a and 404 b can each beplaced in final, negative or female mold halves 1112 a and 1112 b. Thepreformed composite panels 1104 a and 1104 b or composite panels 404 aand 404 b can be configured as mirror images of one another, at leastwith respect to the layup of composite sheets 504 within the panels 404from which the preformed composite panels 1104 a and 1104 b or compositepanels 404 a and 404 b were formed, and with respect to the generaloutline of the edges 516 and 520. In addition, a welding strip 140 canbe attached adjacent the joints between the complementary inside 516 andoutside 520 edges. The preformed composite panels 1104 a and 1104 b orcomposite panels 404 a and 404 b can then be conformed to the shape ofthe final mold 1108 by applying heat and pressure (step 920). Theapplication of pressure can be achieved using a male mold or solidmandrel, such as but not limited to a mandrel formed from a materialwith a high coefficient of thermal expansion, such as silicone.Alternatively, as depicted in FIG. 11, pressure can be applied using aninflatable bladder 1116 placed on a side of the preformed compositepanel 1104 or composite panel 404 opposite the side that is adjacent tothe final mold 600. In addition, multiple final molds 1108 can be usedin combination. For example, in the depicted example, the final mold1108 includes complementary first 1112 a and second 1112 b moldcomponents. Where multiple, preformed composite sheets 1104 or compositesheets 504 are placed in complementary final molds 1112 a and 1112 b atthe same time, a single bladder 1116 can be used to apply pressure tothe composite sheets 1104 or 404 simultaneously.

The formed composite structure 104, in the three-dimensional shapeimparted by the final mold 1108, is then cooled and removed from thefinal mold 1108 (step 924). The composite structure 104 is then readyfor final finishing, such as sanding and painting. Individual structures104 formed from one or multiple composite panels 404, can be joinedtogether to form larger composite structures during or after a step offinal molding. Accordingly, the formation of composite structurecomponents 108 in their final form, and the formation of the compositestructure 104 from such components 108, can be performed simultaneously.For instance, as shown in FIG. 11, multiple preformed composite panels1104 and/or multiple composite panels 404 can be fused to one anotherduring a step of final molding. As another example, composite structures104 can be joined together after final molding by fusing or bonding thedifferent structures, including unitary or multiple component structures104, to one another, forming a larger composite structure. Fusing caninclude reheating the individual structure in the area of the joint to atemperature that is at or less than the melting point of the composite,and at or higher than the heat deflection temperature, per ASTM D648, ofthe composite. As still another example, structures 100 formed frommultiple sub-structures can be bonded to one another using an adhesive.The joint at the seam or interface between the individual compositestructures can be a butt joint, a lap joint, or can include differenttypes of joints at different locations.

As discussed herein, the composite sheets 504 can include one or moresheets having a large number of randomly oriented fibers 512 that areimpregnated in a thermoplastic material 508. More particularly, thefibers 512 are randomly oriented in at least a plane encompassing theedges of the composite sheet 504 while that sheet is held flat. Thecomposite sheet 504 is relatively thin, for example, but withoutlimitation, having a thickness of from about 2 mm to about 4 mm. Thefibers 512 in such a sheet 504 are relatively short, having, forexample, but without limitation, a length of from about 4 mm to about 30mm. Moreover, fibers 512 of different lengths can be incorporated into asingle composite sheet 504. In accordance with the exemplary embodimentsof the present disclosure, the composite sheets 504 includes from about1 gram per cubic centimeter to about 2 grams per cubic centimeter offibers 512. By volume, the ratio of fibers 512 to thermoplastic material508 can be selected such that from 20% to 70% of the volume comprisesfibers 512, and such that the remainder of the volume comprises thethermoplastic material 508. The fibers 512 of a sheet 504 having aunidirectional, woven, or random orientation can comprise fibers havinga selected tensile strength. For example, the fibers 512 can have a highmodulus or stiffness and/or high tensile strength (e.g. a modulusgreater than 280 Gpa and a tensile strength greater than 2,500 Mpa), andcan comprise carbon fibers. As another example, fibers 512 of differenttensile strengths can be included in a single composite sheet 504. Inaccordance with at least some embodiments of the present disclosure, thefibers 512 may comprise recycled materials. For instance, the fibers 512may be obtained from cuttings created in forming sheets of traditional,continuous ply carbon fiber materials. The thermoplastic material 508can comprise any material that can be formed or re-formed by heating.For example, the thermoplastic material 508 may comprise a polyamide ora thermoplastic resin. In accordance with exemplary embodiments of thepresent disclosure, the composite sheet 504 weighs from about 1.2 g/ccto about 1.8 g/cc.

According to at least some embodiments of the present disclosure,composite structures 104 or composite structure components 108 areformed by molding one or more composite panels 404 that each include oneor more composite sheets 504 containing a thermoplastic material 508 andfibers 512 impregnated with the thermoplastic material 508 into adesired three-dimensional configuration. In accordance with furtherembodiments of the present disclosure, multiple composite structurecomponents 108 can be fused or otherwise joined together to form acomposite structure 104. In accordance with still further embodiments,the formation of a composite structure 104 containing multiple compositestructure components 108 that are fused to one another can be performedsimultaneously with the molding or final molding of composite panels 404into the respective composite structure components 108. Moreover,components formed from metal or other materials may be fused to one ormore of the composite structure components 108 at the same time that thecomposite structure components 108 are fused to one another to form thecomposite structure 104.

In accordance with at least some embodiments of the present disclosure,the technology encompasses:

(1) A composite structure, comprising:

a first component part, the first component part including:

-   -   a first sheet of thermoplastic fiber reinforced material,        wherein the first sheet has an outsider perimeter, wherein a        least a first aperture is formed in the first sheet of        thermoplastic fiber reinforced material, and wherein the at        least a first aperture is spaced apart from the outside        perimeter;

a second component part, the second component part including:

-   -   a second sheet of thermoplastic fiber reinforced material,        wherein the second sheet has an outside perimeter, wherein at        least a first aperture is formed in the second sheet of        thermoplastic fiber reinforced material, wherein the at least a        first aperture is spaced apart from the outside perimeter,        wherein the first component part is joined to the second        component part, and wherein an interior volume is formed between        at least a first portion of the first component part and a first        portion of the second component part.

(2) The composite structure of (1), wherein the outside perimeter of thefirst sheet forms at least a portion of a first outside edge section ofthe first component part, wherein the outside perimeter of the secondsheet forms at least a portion of a first outside edge section of thesecond component part, and wherein the first outside edge section of thefirst component part is joined to the first outside edge section of thesecond component part.

(3) The composite structure of (1) or (2), wherein the at least a firstaperture of the first sheet forms at least a portion of a first insideedge section of the first component part, wherein the first aperture ofthe second sheet forms at least a portion of a first inside edge sectionof the second component part, and wherein the first inside edge sectionof the first component part is joined to the first inside edge sectionof the second component part.

(4) The composite structure of any of (1) to (3), wherein a firstportion of the outside perimeter of the first sheet forms a firstoutside edge section of the first component part, wherein a secondportion of the outside perimeter of the first sheet forms a secondoutside edge portion of the first component part, and wherein the secondoutside edge section of the first component part is separated from thesecond outside edge section of the first component part.

(5) The composite structure of any of (1) to (4), wherein the firstsheet includes a first plurality of fibers, wherein one end of eachfiber in the first plurality of fibers forms a portion of an outsideperimeter of the first component part, wherein another end of each fiberin a first subset of the first plurality of fibers forms a portion ofanother portion of the outside perimeter of the first component part,and wherein another end of each fiber in a second subset of theplurality of fibers forms a portion of an insider perimeter of the firstcomponent part.

(6) The composite structure of any of (1) to (5), wherein the secondsheet includes a first plurality of fibers, wherein one end of eachfiber in the first plurality of fibers forms a portion of an outsideperimeter of the second component part, wherein another end of eachfiber in a first subset of the first plurality of fibers forms a portionof another portion of the outside perimeter of the second componentpart, and wherein another end of each fiber in a second subset of theplurality of fibers forms a portion of an insider perimeter of thesecond component part.

(7) The composite structure of any of (1) to (6), wherein the firstcomponent part further includes:

a third sheet of thermoplastic fiber reinforced material, wherein thethird sheet has an outsider perimeter, wherein a least a first apertureis formed in the third sheet of thermoplastic fiber reinforced material,wherein the at least a first aperture is spaced apart from the outsideperimeter, wherein the third sheet includes a first plurality of fibers,wherein one end of each fiber in the first plurality of fibers forms aportion of an outside perimeter of the first component part, whereinanother end of each fiber in a first subset of the first plurality offibers forms a portion of another portion of the outside perimeter ofthe first component part, and wherein another end of each fiber in asecond subset of the plurality of fibers forms a portion of an insideperimeter of the first component part.

(8) The composite structure of any of (1) to (6), wherein the firstcomponent part further includes:

at third sheet of thermoplastic fiber reinforced material, wherein thethird sheet includes a plurality of randomly oriented carbon fibers.

(9) The composite structure of (7) or (8), wherein the third sheet isexterior to the interior volume.

(10) The composite structure of any of (1) to (9), further comprising:

a first welding strip, wherein the first welding strip extends along ajoint between the first outside edge section of the first component partand the first outside edge section of the second component part.

In accordance with further aspects of the present disclosure, thetechnology encompasses:

(11) A composite panel, comprising:

a first sheet, the first sheet including:

-   -   a plurality of fibers;    -   a thermoplastic material, wherein the fibers are embedded in the        thermoplastic material; and    -   an aperture;

a second sheet, the second sheet including:

-   -   a plurality of fibers;    -   a thermoplastic material, wherein the fibers are embedded in the        thermoplastic material; and    -   an aperture,

wherein the first sheet is joined to the second sheet, and wherein atleast a portion of the aperture of the first sheet is aligned with atleast a portion of the aperture of the second sheet to form an aperturein the composite panel.

(12) The composite panel of (11), wherein the first sheet has edges thatdefine a perimeter, wherein the aperture of the first sheet is entirelywithin the perimeter of the first sheet, wherein the second sheet hasedges that define a perimeter, and wherein the aperture of the secondsheet is entirely within the perimeter of the second sheet.

(13) The composite panel of (12), wherein the perimeter of the firstsheet includes at least a first side edge and a second side edge,wherein at least some of the fibers included in the plurality of fibersof the first sheet extend from the first side edge to the second sideedge, and wherein at least most of the fibers included in the pluralityof fibers of the second sheet are not parallel the fibers included inthe plurality of fibers of the first sheet.

(14) The composite panel of any of (11) to (13), wherein the fibersincluded in the plurality of fibers of the second sheet are orientedrandomly with respect to a plane extending across the edges of thesecond sheet.

In accordance with still other aspects of the present disclosure, thetechnology encompasses:

(15) A method of forming a composite structure, comprising:

forming a first composite panel, wherein the first composite panelincludes at least a first sheet of a thermoplastic material containing aplurality of fibers, and wherein at least one aperture is formed in thefirst composite panel;

heating the first composite panel;

placing the heated first composite panel in a first final mold, whereinthe first composite panel is given a first final contour.

(16) The method of (15), further comprising:

forming a second composite panel, wherein the second composite panelincludes at least a second sheet of a thermoplastic material containinga plurality of fibers;

heating the second composite panel;

placing the heated second composite panel in the first final mold,wherein the second composite panel is given a second final contour, andwherein the second composite panel is fused to the first compositepanel.

(17) The method of (15) or (16), wherein forming the first compositepanel includes joining the first sheet to another sheet of thermoplasticmaterial using heat and pressure.

(18) The method of any of (15) to (17), wherein the first sheet includesa plurality of randomly oriented fibers.

(19) The method of any of (15) to (17), wherein the first compositepanel includes an outside edge, wherein the first composite panelincludes an inside edge that is coincident with the aperture of thefirst composite panel, wherein at least one aperture is formed in thesecond composite panel, wherein the second composite panel includes anoutside edge, wherein the second composite panel includes an inside edgethat is coincident with the aperture of the second composite panel,wherein at least a portion of the outside edge of the first compositepanel is fused to at least a portion of the outside edge of the secondcomposite panel, wherein at least a portion of the inside edge of thefirst composite panel is fused to at least a portion of the inside edgeof the second composite panel, and wherein fusing the respective edgesof the first and second composite panels is performed simultaneously.

(20) The method of any of (15) to (19), wherein the first and secondcomposite panels are formed at a temperature greater than a meltingpoint of the thermoplastic material, and wherein fusing the firstcomposite panel to the second composite panel at a temperature ofgreater than or equal to a glass transition temperature of thethermoplastic material and less than or equal to the melting point ofthe thermoplastic material.

The foregoing discussion has been presented for purposes of illustrationand description. Further, the description is not intended to limit thedisclosed structures, systems and methods to the forms disclosed herein.Consequently, variations and modifications commensurate with the aboveteachings, within the skill or knowledge of the relevant art, are withinthe scope of the present disclosure. The embodiments describedhereinabove are further intended to explain the best mode presentlyknown of practicing the disclosed structures, systems and methods, andto enable others skilled in the art to utilize the disclosed structures,systems and methods in such or in other embodiments and with variousmodifications required by the particular application or use. It isintended that the appended claims be construed to include alternativeembodiments to the extent permitted by the prior art.

What is claimed is:
 1. A composite structure, comprising: a firstcomponent part, the first component part including: a first sheet ofthermoplastic fiber reinforced material, wherein the first sheet has anoutsider perimeter, wherein a least a first aperture is formed in thefirst sheet of thermoplastic fiber reinforced material, and wherein theat least a first aperture is spaced apart from the outside perimeter; asecond component part, the second component part including: a secondsheet of thermoplastic fiber reinforced material, wherein the secondsheet has an outside perimeter, wherein at least a first aperture isformed in the second sheet of thermoplastic fiber reinforced material,wherein the at least a first aperture is spaced apart from the outsideperimeter, wherein the first component part is joined to the secondcomponent part, and wherein an interior volume is formed between atleast a first portion of the first component part and a first portion ofthe second component part.
 2. The composite structure of claim 1,wherein the outside perimeter of the first sheet forms at least aportion of a first outside edge section of the first component part,wherein the outside perimeter of the second sheet forms at least aportion of a first outside edge section of the second component part,and wherein the first outside edge section of the first component partis joined to the first outside edge section of the second componentpart.
 3. The composite structure of claim 2, wherein the at least afirst aperture of the first sheet forms at least a portion of a firstinside edge section of the first component part, wherein the firstaperture of the second sheet forms at least a portion of a first insideedge section of the second component part, and wherein the first insideedge section of the first component part is joined to the first insideedge section of the second component part.
 4. The composite structure ofclaim 1, wherein a first portion of the outside perimeter of the firstsheet forms a first outside edge section of the first component part,wherein a second portion of the outside perimeter of the first sheetforms a second outside edge portion of the first component part, andwherein the second outside edge section of the first component part isseparated from the second outside edge section of the first componentpart.
 5. The composite structure of claim 1, wherein the first sheetincludes a first plurality of fibers, wherein one end of each fiber inthe first plurality of fibers forms a portion of an outside perimeter ofthe first component part, wherein another end of each fiber in a firstsubset of the first plurality of fibers forms a portion of anotherportion of the outside perimeter of the first component part, andwherein another end of each fiber in a second subset of the plurality offibers forms a portion of an insider perimeter of the first componentpart.
 6. The composite structure of claim 5, wherein the second sheetincludes a first plurality of fibers, wherein one end of each fiber inthe first plurality of fibers forms a portion of an outside perimeter ofthe second component part, wherein another end of each fiber in a firstsubset of the first plurality of fibers forms a portion of anotherportion of the outside perimeter of the second component part, andwherein another end of each fiber in a second subset of the plurality offibers forms a portion of an insider perimeter of the second componentpart.
 7. The composite structure of claim 6, wherein the first componentpart further includes: a third sheet of thermoplastic fiber reinforcedmaterial, wherein the third sheet has an outsider perimeter, wherein aleast a first aperture is formed in the third sheet of thermoplasticfiber reinforced material, wherein the at least a first aperture isspaced apart from the outside perimeter, wherein the third sheetincludes a first plurality of fibers, wherein one end of each fiber inthe first plurality of fibers forms a portion of an outside perimeter ofthe first component part, wherein another end of each fiber in a firstsubset of the first plurality of fibers forms a portion of anotherportion of the outside perimeter of the first component part, andwherein another end of each fiber in a second subset of the plurality offibers forms a portion of an inside perimeter of the first componentpart.
 8. The composite structure of claim 1, wherein the first componentpart further includes: at third sheet of thermoplastic fiber reinforcedmaterial, wherein the third sheet includes a plurality of randomlyoriented carbon fibers.
 9. The composite structure of claim 8, whereinthe third sheet is exterior to the interior volume.
 10. The compositestructure of claim 4, further comprising: a first welding strip, whereinthe first welding strip extends along a joint between the first outsideedge section of the first component part and the first outside edgesection of the second component part.
 11. A composite panel, comprising:a first sheet, the first sheet including: a plurality of fibers; athermoplastic material, wherein the fibers are embedded in thethermoplastic material; and an aperture; a second sheet, the secondsheet including: a plurality of fibers; a thermoplastic material,wherein the fibers are embedded in the thermoplastic material; and anaperture, wherein the first sheet is joined to the second sheet, andwherein at least a portion of the aperture of the first sheet is alignedwith at least a portion of the aperture of the second sheet to form anaperture in the composite panel.
 12. The composite panel of claim 11,wherein the first sheet has edges that define a perimeter, wherein theaperture of the first sheet is entirely within the perimeter of thefirst sheet, wherein the second sheet has edges that define a perimeter,and wherein the aperture of the second sheet is entirely within theperimeter of the second sheet.
 13. The composite panel of claim 12,wherein the perimeter of the first sheet includes at least a first sideedge and a second side edge, wherein at least some of the fibersincluded in the plurality of fibers of the first sheet extend from thefirst side edge to the second side edge, and wherein at least most ofthe fibers included in the plurality of fibers of the second sheet arenot parallel the fibers included in the plurality of fibers of the firstsheet.
 14. The composite panel of claim 13, wherein the fibers includedin the plurality of fibers of the second sheet are oriented randomlywith respect to a plane extending across the edges of the second sheet.15. A method of forming a composite structure, comprising: forming afirst composite panel, wherein the first composite panel includes atleast a first sheet of a thermoplastic material containing a pluralityof fibers, and wherein at least one aperture is formed in the firstcomposite panel; heating the first composite panel; placing the heatedfirst composite panel in a first final mold, wherein the first compositepanel is given a first final contour.
 16. The method of claim 15,further comprising: forming a second composite panel, wherein the secondcomposite panel includes at least a second sheet of a thermoplasticmaterial containing a plurality of fibers; heating the second compositepanel; placing the heated second composite panel in the first finalmold, wherein the second composite panel is given a second finalcontour, and wherein the second composite panel is fused to the firstcomposite panel.
 17. The method of claim 16, wherein forming the firstcomposite panel includes joining the first sheet to another sheet ofthermoplastic material using heat and pressure.
 18. The method of claim17, wherein the first sheet includes a plurality of randomly orientedfibers.
 19. The method of claim 17, wherein the first composite panelincludes an outside edge, wherein the first composite panel includes aninside edge that is coincident with the aperture of the first compositepanel, wherein at least one aperture is formed in the second compositepanel, wherein the second composite panel includes an outside edge,wherein the second composite panel includes an inside edge that iscoincident with the aperture of the second composite panel, wherein atleast a portion of the outside edge of the first composite panel isfused to at least a portion of the outside edge of the second compositepanel, wherein at least a portion of the inside edge of the firstcomposite panel is fused to at least a portion of the inside edge of thesecond composite panel, and wherein fusing the respective edges of thefirst and second composite panels is performed simultaneously.
 20. Themethod of claim 16, wherein the first and second composite panels areformed at a temperature greater than a melting point of thethermoplastic material, and wherein fusing the first composite panel tothe second composite panel at a temperature of greater than or equal toa glass transition temperature of the thermoplastic material and lessthan or equal to the melting point of the thermoplastic material.